Decoy flare

ABSTRACT

An infrared (IR) decoy flare for a helicopter, or an aircraft with a similar size engine, the flare including a casing, at least two longitudinal flare pellets in the casing, a single impulse cartridge to serially expel and ignite the pellets, and a delay element associated with at least one of the flare pellets and arranged to be ignited by the impulse cartridge and to expel the associated flare pellet a predetermined interval after ignition.

FIELD OF THE INVENTION

[0001] The present invention relates to decoy flares, in general, and, in particular, to decoy flares for helicopters.

BACKGROUND OF THE INVENTION

[0002] Infrared (IR) decoy flares are the primary countermeasure for protecting aircraft and helicopters against air-to-air and ground-to-air heat-seeking missiles. Conventional IR decoy flares consist of a rectangular cross-section aluminum case, which may be eight inches long, housing the flare pellet and a safe-and-initiate mechanism to ensure that the flare does not ignite while still in the aircraft. Pellets are formed by the extrusion of a pyrotechnic formulation, which is cut to length and wrapped in a heavy aluminum foil.

[0003] An electric squib (impulse cartridge) expels the pellet/safe-and-initiate mechanism assembly. When clear of the aircraft, the safe-and-initiate mechanism ignites the flare pellet. A thermal signature is produced by the burning pellet that is greater than that of the engine itself. The lock of the IR seeker in the attacking missile on the aircraft engine exhaust is broken, allowing the aircraft to escape.

[0004] Such flares have been employed in helicopters, as well as in airplanes. However, a helicopter engine provides substantially less IR radiation than does an airplane engine, with the result that conventional decoy flares provide radiation intensity which is substantially higher than necessary.

[0005] It is also known, such as from U.S. Pat. No. 4,621,579 and U.S. Pat. No. 5,400,690, to launch a plurality of decoys, one after another, from a plane or ship to create an artificial moving target. However, many of the systems in these patents include a separate ignition disintegrator unit, and a separate electrically actuated ignition element for each decoy, such that each decoy is launched separately.

[0006] Accordingly, there is a long felt need for and it would be very desirable to have a relatively simple decoy flare for helicopters which would provide an IR output similar to a helicopter engine, which would provide protection for a significantly longer time than is possible at present, but which would not require a larger storage volume than is utilized at present.

SUMMARY OF THE INVENTION

[0007] According to the present invention, there is provided an infrared (IR) decoy flare for a helicopter, or an aircraft with an engine of similar size, including a casing, at least two longitudinal flare pellets in the casing, a single impulse cartridge to serially expel and ignite the pellets, and a delay element associated with at least one of the flare pellets arranged to be ignited by the impulse cartridge and to expel the associated flare pellet after a predetermined interval.

[0008] According to a preferred embodiment of the invention, the delay element includes an ignition compound, a delay compound and an impulse compound.

[0009] Further according to a preferred embodiment, the decoy flare includes three longitudinal decoy pellets in the casing, and two of the decoy pellets are associated with delay elements for expulsion after different predetermined time intervals.

[0010] There is also provided in accordance with the present invention a method of creating an IR decoy trail from a helicopter, the method including providing at least two decoy pellets in a single casing, and activating an impulse cartridge to ignite and expel a first one of the decoy pellets while simultaneously igniting delay elements associated with each of the other decoy pellets for subsequent serial ignition and expulsion.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present invention will be further understood and appreciated from the following detailed description taken in conjunction with the drawings in which:

[0012]FIG. 1 is a side sectional view of an IR decoy flare constructed and operative in accordance with one embodiment of the invention;

[0013]FIG. 2 is a schematic sectional view of the casing of the flare of FIG. 1; and

[0014]FIG. 3 is an exploded perspective view of an IR decoy flare constructed and operative in accordance with an alternative embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0015] The present invention relates to infrared (IR) decoy flares for use in helicopters, and other light aircraft. For ease of discussion, the invention will be described throughout the specification and claims with reference to helicopters, however it will be appreciated that it also relates to any other aircraft having an engine of similar size.

[0016] The IR decoy flare of the invention includes a casing of conventional size, which may be a conventional aluminum casing of rectangular cross-section, a plurality of decoy pellets, and an impulse cartridge, such as a conventional standard electric squib. The novelty in the present invention lies in the fact that the single casing holds a plurality of longitudinal pellets or radiant bodies, not a single pellet as known in conventional flares, and that a single impulse cartridge serially expels all the pellets at predetermined intervals from the helicopter. Thus, in the case where the flare includes three pellets, the protection time provided to the helicopter for a given volume of decoy flares is effectively tripled.

[0017] Referring now to FIG. 1, there is shown a side sectional view of an IR decoy flare 10 constructed and operative in accordance with one embodiment of the invention. Flare 10 includes a casing 12, shown in detail in FIG. 2, which may be a rectangular casing of standard dimensions, with partitions 14 defining at least two, and preferably three, longitudinal compartments 16, here shown as three. An ignition chamber 18 is provided to hold an impulse cartridge 20, which may be any standard squib. Ignition chamber 18 defines an aperture 22 into each compartment 16.

[0018] Operation of the decoy flare of this embodiment is as follows. A longitudinal flare pellet 24 of any conventional pyrotechnic composition, such as magnesium Teflon viton (MTV), is inserted into each compartment 16 in casing 12. A delay element 26, 28 is inserted in each compartment 16 except one. Delay elements 26 and 28 preferably include an ignition compound 30, such as AlA, a delay compound 32, 32 such as a mixture of tungsten (2-3 potassium perchlorate and silicon dioxide, and an impulse compound 34, such as black powder.

[0019] The delay compounds 32 and 32 so as to provided ejection of the associated pellets at desired predetermined intervals after the first. Thus, as will be appreciated by those skilled in the art, delay compound 32 can be a different compound from compound 32, having a slower combustion rate, or compounds 32 and 32 with different quantities being provided in the various compartments. An impulse cartridge 20 is inserted into ignition chamber 18 and the flare is closed.

[0020] When the flare is to be used, impulse cartridge 20 is activated, as known, which in turn ignites and expels a first flare pellet 24. Simultaneously, through apertures 22, impulse cartridge 20 ignites the ignition compounds 30 of first and second delay elements 26, 28. Ignition compound 30 ignites first and second delay compounds 32, 32 different predetermined intervals, ignite impulse compounds 34 to expel and ignite the associated flare pellets 24 24 pellets of intensity approximating that of a helicopter engine are ejected, at predetermined intervals t1 and t2, to provide protection to the helicopter.

[0021] Referring now to FIG. 3, there is shown an exploded view of a decoy flare constructed and operative in accordance with an alternative embodiment of the present invention. Flare 40 includes a casing 42, which is a conventional rectangular casing of standard dimensions. Mounted in casing 42 is a flare housing 44 including partitions 46 defining at least two, and preferably three, longitudinal compartments 48, here shown as three. Decoy flare 40 also includes a delay housing 50 having delay compartments 52 for holding delay compounds associated with each of the flare pellets except one. Delay housing 50 includes an aperture 54 into each compartment 52. An impulse cartridge 56, which may be any standard squib, is inserted in delay housing 50.

[0022] Operation of this embodiment of the invention is as follows. A delay housing 50 is slid into casing 42. A plastic piston 58 is affixed to the end of each longitudinal flare (not shown). Piston 58 serves to ensure proper ejection of the flare pellet, as known in conventional flares. Flare housing 44 is inserted into casing 42 and the flares are inserted into each compartment 48. Casing 42 is closed with a cap 60. Finally, an impulse cartridge 56 is placed in casing 42 adjacent delay housing 50.

[0023] Activation of the flare is substantially the same as described hereinabove. The impulse cartridge is activated, thereby expelling one longitudinal flare from its compartment 48, and simultaneously igniting delay compounds in delay housing 50. When the first delay compound ignites its respective impulse compound, the second flare is expelled from the helicopter. Similarly, when the second delay compound ignites its respective impulse compound, the third flare is expelled from the helicopter, and so on until all the flares are ejected.

[0024] It will be appreciated that the invention is not limited to what has been described hereinabove merely by way of example. Rather, the invention is limited solely by the claims which follow. 

1. An infrared (IR) decoy flare for a helicopter, or an aircraft with a similar size engine, said flare comprising: a) a casing; b) at least two longitudinal flare pellets in said casing; c) a single impulse cartridge to serially expel and ignite said pellets; and d) a delay element associated with at least one of said flare pellets and arranged to be ignited by said impulse cartridge and to expel said associated flare pellet a predetermined interval after said ignition.
 2. The infrared decoy flare according to claim 1, wherein said delay element includes an ignition compound, a delay compound and an impulse compound.
 3. The infrared decoy flare according to either of claims 1 and 2, wherein said decoy flare includes three decoy pellets in said casing, and two of said decoy pellets are associated with delay elements for expulsion from the helicopter after different predetermined time intervals.
 4. A method of creating an infrared decoy trail from a helicopter, or an aircraft with a similar size engine, the method comprising: a) providing at least two longitudinal decoy pellets in a single casing; and b) activating an impulse cartridge to expel and ignite a first one of said decoy pellets while simultaneously igniting delay elements associated with each of the other decoy pellets for expulsion of said other decoy pellets from the helicopter after different predetermined delay times. 